Physics Van 3-site Navigational Menu

Physics Van Navigational Menu

Q & A: Some Battery Basics

Learn more physics!

Most recent answer: 12/27/2015
I have installed a B-35 12V 35W 35W high/low beam to my beachcruiser..i need to get me 16 miles a day ride home..need to know what kind of battery to buy to make them run properly..yes its an after after market motorcycle headlight..and i know ill need a charger..just want the right size please?
- Maurizio (age 24)

Ciao Maurizio,

For a given battery voltage the amount of current required is  I = W/V.  In your case W = 35 Watts, so I = 35/12 = 2.9 Amperes.   The storage capacity of a battery is expressed in Ampere-hours The more Ah a battery has the more expensive it is.     So, for example, if your boat ride home takes one hour then you need at least a 3 Ampere-Hour battery.   It's best to have plenty to spare in case of emergency.



(published on 12/27/2015)

Follow-up on this answer.